Medicine
The heart pump that floats on magnets
A coin-sized impeller that keeps blood moving for people whose hearts are too weak.
- Speed
- about 3,000–9,000 RPM
- Flow
- up to about 10 L/min
- Impeller
- about the size of a coin
- Bearings
- none — magnetic levitation
Numbers are rounded, typical values — real machines vary.
What it does
When a heart becomes too weak to pump enough blood, doctors can implant a small pump — a left ventricular assist device — that takes blood from the heart and pushes it into the aorta, the body’s main artery.
Many modern ones are tiny : blood enters at the , the vanes fling it outward, and a little guides it to the outlet.
Why magnets?
Blood cells are fragile. Squeezing them through tight gaps or rubbing damages them, and bearings would wear out inside a body.
So the best designs hold the impeller in place with magnetic fields: it spins without touching anything, with wide, smooth gaps and gentle .
Physics you already know
The pump only has to add a modest — enough to match the pressure in the arteries — at a few litres per minute. Its speed can be adjusted, and the flow follows the .